An investigation has been made of processes responsible for the growth, damping, and propagation characteristics of whistler mode emissions within the earth's plasmasphere. Three-dimensional ray path calculations of the integrated wave gain in a realistic model plasmsphere have provided an explicit confirmation of the anisotropic electron cyclotron resonant generation mechanism for the maintenance of plasmaspheric hiss. Peak wave amplification occurs for field-aligned waves in the outer plasmasphere. The majority of unstable low-frequency waves follow ray trajectories that internally reflect at the plasmapause and are thus trapped within the plasmasphere. This reflection allows waves to subsequently propagate into the locally stable inner and midddle plasmasphere and also migrate substantially in longitude. The combination of internal reflection at the plasmapause and magnetospheric reflection at high latitude provide an important class of wave trajectories that are recycled back to the equatorial growth region with sufficiently small wave normal angles to allow further cyclotron resonant amplification. It is unlikely that wave growth can occur from the natural incoherent emissivity level within the plasmasphere since the required gains (≈100 dB) would mandate unreasonably high energetic electron flux. An alternate, as yet unidentified, embryonic source is therefore required to initiate the growth process. But once established the observed spectrum of broad band plasmaspheric hiss can be maintained by the modest net gains anticipated along ray trajectories that are recycled back to the favorable equatorial growth region. A simulation of the spectral properties of waves arriving at selected observation points following several equatorial transits shows that the largest accumulated gain occurs for recycled waves that reflect from the plasmapause following each equatorial crossing. Furthermore, the peak gain is relatively insensitive to the location of the observation point, and waves are expected to arrive over a broad solid angle in k space consistent with observations. The ability of wves to gain access to regions far from the source is a direct result of the relatively weaker Landau damping of oblique waves along the high latitude portion of the recycled ray path in comparison to the equatorial cyclotron resonant growth. The hiss upper frequency cutoff can result from the limited anisotropy of the cyclotron resonant electrons, the more severe Landau damping at higher frequencies, or in part, from the decreased ability of the higher frequency waves to recycle and thus experience multitransit growth. The characteristic lower frequency cutoff can be due to either the decrease in flux of energetic electrons that cyclotron resonate with the lower frequency waves or from thermal electron Landau damping should the plasmaspheric electron temperature exceed several electron volts. |